Method, and related apparatus for recovering called service of terminal

Abstract

Embodiments of the present invention disclose a method, a related apparatus, and a system for recovering a called service of a terminal. The method includes: when a called request of a user terminal is received, querying an initial proxy-call session control function (P-CSCF) entity with which the user terminal currently registers; if it is detected that the initial P-CSCF is faulty, selecting an available P-CSCF and sending, to the available P-CSCF, a notification message that carries a redundancy identifier, where the redundancy identifier is used to instruct the available P-CSCF to trigger the user terminal to re-register with the P-CSCF; and when a registration complete message sent by the P-CSCF with which the user terminal re-registers is received, delivering the called request to the re-registered P-CSCF to bear a called service of the user terminal.

What is claimed is: 
     
       1. A method for recovering a called service of a terminal performed by a Serving Call Session Control Function (S-CSCF), the method comprising:
 receiving a called request of the user terminal; 
 querying an initial proxy-call session control function (P-CSCF) entity with which the user terminal currently registers; 
 detecting that the initial P-CSCF is faulty; 
 selecting an available P-CSCF; 
 notifying the available P-CSCF to trigger the user terminal to re-initiate IP Multimedia Subsystem (IMS) registration, wherein the available P-CSCF triggers, by using a policy and charging rules function (PCRF) entity, the user terminal to re-initiate IMS registration; and 
 delivering the called request to a re-registered P-CSCF to bear the called service of the user terminal after the user terminal completes the IMS registration. 
 
     
     
       2. The method according to  claim 1 , wherein notifying the available P-CSCF to trigger the user terminal to re-initiate IMS registration comprises:
 sending, to the available P-CSCF, a notification message that carries a redundancy identifier, wherein the redundancy identifier is used to instruct the available P-CSCF to trigger the user terminal to re-initiate the IMS registration. 
 
     
     
       3. The method according to  claim 1 , wherein notifying the available P-CSCF to trigger the user terminal to re-initiate IMS registration comprises:
 sending the called request of the user terminal to the available P-CSCF; and 
 when the available P-CSCF determines that no registration data of a called user is stored, triggering the user terminal to re-initiate the IMS registration. 
 
     
     
       4. The method according to  claim 1 , wherein before the selecting an available P-CSCF, the method further comprises:
 configuring a first identifier and a second identifier for the initial P-CSCF, wherein the first identifier comprises an internet protocol (IP) address of the initial P-CSCF, and the second identifier comprises an IP address of a P-CSCF except the initial P-CSCF. 
 
     
     
       5. The method according to  claim 4 , wherein configuring the first identifier and the second identifier for the initial P-CSCF comprises:
 configuring, on a domain name system (DNS) server, the first identifier and the second identifier according to a host name of the initial P-CSCF. 
 
     
     
       6. The method according to  claim 4 , wherein selecting the available P-CSCF and notifying the available P-CSCF, if it is detected that the initial P-CSCF is faulty comprises:
 acquiring the first identifier and the second identifier that are configured for the initial P-CSCF; 
 if it is detected, according to the acquired first identifier, that the initial P-CSCF corresponding to the first identifier is faulty, using a P-CSCF corresponding to the second identifier as the available P-CSCF; and 
 sending a notification message to the available P-CSCF according to the second identifier. 
 
     
     
       7. The method according to  claim 1 , wherein delivering the called request to the re-registered P-CSCF to bear the called service of the user terminal comprises:
 sending the called request to the re-registered P-CSCF, so that the re-registered P-CSCF sends the called request to the user terminal to perform the called service. 
 
     
     
       8. An apparatus for recovering a called service of a terminal, comprising a processor and a non-transitory computer readable medium containing computer executable instructions stored thereon, such that when the processor executes the instructions, the processor is configured to:
 receive a called request of the user terminal; 
 query an initial proxy-call session control function (P-CSCF) entity with which the user terminal currently registers; 
 detect that the initial P-CSCF is faulty; 
 select an available P-CSCF and notify the available P-CSCF to trigger the user terminal to re-initiate IP Multimedia Subsystem (IMS) registration, wherein the available P-CSCF triggers, by using a policy and charging rules function (PCRF) entity, the user terminal to re-initiate IMS registration; and 
 deliver the called request to a re-registered P-CSCF to bear the called service of the user terminal after the user terminal completes the IMS registration. 
 
     
     
       9. The apparatus according to  claim 8 , wherein the processor is further configured to:
 after selecting the available P-CSCF, send, to the available P-CSCF, a notification message that carries a redundancy identifier, wherein the redundancy identifier is used to instruct the available P-CSCF to trigger the user terminal to re-initiate the IMS registration. 
 
     
     
       10. The apparatus according to  claim 8 , wherein the processor is further configured to:
 after selecting the available P-CSCF, send the called request of the user terminal to the available P-CSCF, so as to trigger, when the available P-CSCF determines that no registration data of a called user is stored, the user terminal to re-initiate the IMS registration. 
 
     
     
       11. The apparatus according to  claim 8 , wherein the processor is further configured to:
 configure a first identifier and a second identifier for the initial P-CSCF, wherein the first identifier comprises an internet protocol (IP) address of the initial P-CSCF, and the second identifier comprises an IP address of a P-CSCF except the initial P-CSCF. 
 
     
     
       12. The apparatus according to  claim 11 , wherein the processor is further configured to:
 configure, on a domain name system (DNS) server, the first identifier and the second identifier according to a host name of the initial P-CSCF. 
 
     
     
       13. The apparatus according to  claim 11 , wherein the processor is further configured to:
 acquire the first identifier and the second identifier that are configured for the initial P-CSCF; 
 if, according to the acquired first identifier, the initial P-CSCF corresponding to the first identifier is faulty, use a P-CSCF corresponding to the second identifier as the available P-CSCF; and 
 send a notification message to the available P-CSCF according to the second identifier. 
 
     
     
       14. The apparatus according to  claim 8 , wherein the processor is further configured to:
 send the called request to the re-registered P-CSCF, so that the re-registered P-CSCF sends the called request to the user terminal to perform the called service.